Impact of Expedited Ureteroscopy on Emergency Department Utilisation in Stented Patients with Urolithiasis

Abstract

Background/Objectives: Ureteric stents are commonly used in the management of urolithiasis but are associated with significant morbidity, leading to unplanned emergency department presentations and increased healthcare utilisation. This study aimed to evaluate whether reducing ureteric stent dwell time from three months to one month was associated with reduced stent-related emergency presentations. Secondary objectives were to assess post-ureteroscopy infective complications and identify predictors of emergency attendance. Methods: A retrospective cohort study was conducted across Western Sydney Local Health District, comparing patients undergoing ureteric stenting prior to ureteroscopy before (n = 189) and after (n = 244) an institutional policy change reducing time to definitive surgery from three months to one month. Patients aged ≥16 years with urolithiasis were included. Results: Following the policy change, mean waiting time for ureteroscopy decreased from 97.3 to 40.6 days. The proportion of patients presenting to the emergency department (ED) for stent-related symptoms decreased from 31.7% to 16.4% (p < 0.001), and mean presentations per patient declined from 0.60 to 0.21 (p < 0.001). Stent irritation accounted for most presentations. Using multivariable analysis, age < 50 years, immunosuppression, and positive pre-operative urine cultures were independently associated with ED attendance. Post-ureteroscopy infective complications were lower in the shortened dwell-time cohort (2.0% vs. 4.2%) but did not reach statistical significance (p = 0.26). Conclusions: Reducing routine ureteric stent dwell time from three months to one month was associated with significantly fewer stent-related emergency presentations. Shorter dwell protocols may reduce patient morbidity and healthcare utilisation and could be associated with lower rates of post-ureteroscopy infective complications.

1. Introduction

Ureteric stents are widely utilised in the management of nephrolithiasis. In clinical practice, they are employed both in emergency settings to relieve renal colic and obstructive pyelonephritis, and also electively to facilitate ureteroscopy (URS) in cases of difficult ureteric access [1]. In addition, despite guideline recommendations generally advising against routine stent placement following uncomplicated ureteroscopy, large contemporary series report post-operative stent utilisation rates of up to 74.8% [2].

Despite their frequent use, ureteric stents are associated with significant patient morbidity, with up to 80% of patients experiencing a constellation of irritative symptoms which include frequency, urgency, dysuria, haematuria [3], and can also affect sexual function [4]. Longer dwell times increase symptom exposure and risk of complications. Post-URS sepsis rates were demonstrated to have a temporal relation with longer ureteric stent dwell times [5], with an approximately nine-fold higher risk among patients with stents in situ for longer than three months [6].

Stent-related morbidity also results in significant healthcare expenditure, impacting healthcare systems and imposing additional direct and indirect financial burdens on patients. Patients managed with ureteric stents demonstrate significantly higher rates of emergency department (ED) presentations while awaiting definitive treatment and incur greater overall costs compared with those undergoing primary URS [7]. On an individual patient level, stent-related morbidity has been observed to result in work incapacity, with patients also bearing the costs of healthcare consultations and pharmacotherapy to mediate symptoms [6]. Despite the relative frequency of these symptoms, it remains difficult to predict which patients will have unplanned emergency encounters following stent insertion. In an observational study, common demographic variables including age, sex and race were demonstrated as possessing poor predictive utility, with chronic opioid use being identified as the only reliable independent predictor of unplanned presentations [8].

Given these concerns, stent dwell times would ideally be minimised to the shortest clinically required period. Animal models suggest that when ureteric stents are used to facilitate renal access, there is minimal additional ureteric dilation beyond 5 days [9]. Observational clinical studies have also demonstrated that almost all URS cases were successful following 14 days of stent dwell time [10]. Therefore, many stents likely remain in situ often longer than is clinically required. Stent dwell times are influenced by a number of factors including institutional protocols, operating theatre access, and waitlist pressures.

There is limited real-world data examining the relationship between stent dwell time, emergency presentations and infective complications both prior to, and following, URS. Additionally, the direct impact of intentionally shortening routine stent dwell time on these outcomes is unclear. The aim of this study is to evaluate whether reducing routine ureteric stent dwell time from three months to one month is associated with a reduction in stent-related emergency presentations, with secondary aims of examining its impact on infective complications and identifying predictors of stent-related presentations.

2. Materials and Methods

A retrospective cohort study was conducted, examining outcomes for patients who had undergone ureteric stent insertion for management of nephrolithiasis in the 1 year before (n = 189) and 1 year after (n = 244) an institutional policy change reduced the interval from stent insertion to definitive URS from within 3 months (Category B) to within 1 month (Category A). Ethical approval was obtained from the Western Sydney Local Health District Human Research Ethics Committee (WSLHD HREC 2021/ETH00918 14 July 2021).

Inclusion criteria were patients aged ≥16 years, who underwent ureteric stent insertion prior to definitive URS for nephrolithiasis management in Western Sydney Local Health District (WSLHD). Exclusion criteria included patients who had comorbidities that would predispose them to infective complications, did not undergo URS following stent, or had stents placed for non-stone indications (e.g., malignant obstruction, ureteric strictures). All cases utilised a Percuflex Plus ureteric stent (Boston Scientific, Marlborough, MA, USA), with stent length and diameter selected at the discretion of the operating surgeon. All patients underwent pre-operative urine culture testing in accordance with institutional protocols. Patients with positive urine cultures were treated with culture-directed antibiotics prior to intervention. Peri-operative antibiotic prophylaxis was used for all cases at induction of anaesthesia, consisting of either a cephalosporin or an aminoglycoside.

Eligible cases were identified through institutional databases using the relevant Medicare Benefits Schedule (MBS) procedural codes for ureteric stent insertion. Electronic medical records, including operation reports, and ED presentation documentation were reviewed to determine inclusion eligibility and record peri-operative outcomes.

The primary outcome assessed was the number of emergency presentations for any stent-related complication while awaiting definitive URS. Stent-related ED attendances were categorised as irritation-related or infection-related, based on contemporaneous clinical documentation recorded at the time of presentation. Where diagnosis was unclear in the documentation, cases were assessed by authors (CZ and AD) on all available clinical data, including history, examination, observations, biochemical results and microbiology results. A diagnosis of infective aetiology required a positive urine culture result, and in its absence, a compatible clinical picture with documented fever and elevated inflammatory markers. Secondary outcomes included post-operative complications following URS and identification of predictors for stent-related emergency presentations using multivariable logistic regression. Covariates included demographics (age, sex), body mass index, diabetes, corticosteroid use, immunosuppression, chronic kidney disease, mean waiting time for surgery, and pre-operative microbiology results (urine and blood cultures). Patients were considered immunosuppressed if they had active malignancy, prior organ transplant, use of systemic immunosuppressive therapy, or conditions associated with impaired immune function, including human immunodeficiency viruses (HIV).

Continuous variables are reported as means with standard deviations. Categorical variables are expressed as counts and percentages and were compared using the chi-square or Fisher’s exact test where appropriate. All statistical tests were two-sided, and a p-value of less than 0.05 was considered statistically significant. Statistical analyses were performed using IBM SPSS Statistics (IBM Corp., Armonk, NY, USA), version 29.

3. Results

Within the study period, 970 patients underwent URS within WSLHD, of whom 433 met the inclusion criteria. A total of 189 patients were included in the pre-policy change cohort and 244 in the post-change cohort. Following implementation of the policy change, the mean waiting time for elective URS was reduced from 97.3 days to 40.6 days. Baseline demographics and comorbidities were comparable between groups and are summarised in

Table 1. Demographics and comorbidities.

Demographics	Pre-Policy Change (n = 189)	Post-Policy Change (n = 244)	p-Value
Sex; male (%)	127 (67.2%)	173 (70.9%)	0.462
Age; years (Mean ± SD)	50.4 (±14.5)	50.1 (±16.0)	0.837
BMI; kg/m2 (Mean ± SD)	31.2 (±7.4)	29.9 (±7.5)	0.079
Comorbidities
Pre-existing SPC/IDC (%)	5 (2.6%)	3 (1.2%)	0.304
Type II DM (%)	35 (18.5%)	44 (18.0%)	0.901
Use of steroids (%)	2 (1.1%)	2 (0.8%)	1.000
Immunosuppression (%)	1 (0.5%)	8 (3.3%)	0.084
Chronic kidney disease (%)	6 (3.2%)	7 (2.9%)	1.000

SD: standard deviation; BMI: body mass index; SPC/IDC: suprapubic catheter/indwelling catheter; DM: diabetes mellitus.

. The mean age was 50.4 years in the pre-change cohort and 50.1 years in the post-change cohort, and the majority of patients were male (67.2% and 70.9%, respectively).

A total of 189 ED presentations occurred whilst patients were awaiting URS, comprising 125 presentations in the pre-change cohort and 64 presentations in the post-change cohort (

Table 2. ED presentations and causes during stent dwell (pre-URS).

	Pre-Policy Change (n = 189)	Post-Policy Change (n = 244)	p-Value
Total Presentations to ED (n)	125	64	<0.001
Irritation-related (n)	113	51
Infection-related (n)	12	13
Patients presenting to ED for stent symptoms (%)	60 (31.7%)	40 (16.4%)	<0.001
Average no. of presentations for stent irritation (Mean ± SD)	0.6 (±1.46)	0.21 (±0.74)	<0.001
Cost of ED presentation with stent irritation	$101,117	$51,099

ED: emergency department; URS: ureteroscopy; SD: standard deviation.

). Stent irritation accounted for the majority of presentations, with 113 events in the pre-change group compared with 51 events in the post-change group. The proportion of patients with at least one emergency department presentation significantly decreased following policy change, from 31.7% to 16.4% (p < 0.001). Similarly, the mean number of presentations per patient also decreased, from 0.60 (±1.46) to 0.21 (±0.74) in the post-change cohort (p < 0.001).

Regarding multivariable logistic regression, several factors were independently associated with an increased likelihood of ED presentation for stent irritation while awaiting URS. These included patients aged <50 years, immunosuppression, and positive pre-operative urine culture findings (including both mixed growth and isolated growth cultures). Full effect estimates and 95% confidence intervals are presented in

Table 3. Multivariable predictors of ED presentation due to stent irritation.

	Stent Irritation (OR)	p-Value	95% CI
Age < 50	2.275	0.017	1.160–4.461
Immunosuppression	5.273	0.041	1.071–25.954
Mixed growth on urine MCS pre-operatively	4.397	0.009	1.444–13.394
Isolated organism on urine MCS pre-operatively	3.146	0.020	1.194–8.290

OR: odds ratio; CI: confidence interval; MCS: microscopy, culture, and sensitivity.

.

Infective complications within 30 days post-URS occurred in 8 of 189 patients (4.2%) in the pre-change cohort and in 5 of 244 patients (2.0%) in the post-change cohort. The difference was not statistically significant (p = 0.26).

4. Discussion

Nephrolithiasis is a highly prevalent disease worldwide, with a rising incidence [11]. While ureteric stents are widely used in its management, they are frequently associated with significant stent-related morbidity. It is believed that stent-related flank pain and irritation results from direct contact of the distal coil with the bladder mucosa, as well as from vesicoureteric reflux. Additionally, physical activity may perpetuate distal coil movement and potentially worsen symptoms of frequency and urgency [12]. These symptoms can lead to significant detrimental impacts on quality of life [3] and do not resolve until removal of the ureteric stent [13].

Unsurprisingly, ureteric stents can often lead to unplanned ED visits and higher rates of opioid prescriptions. In one study, the placement of a stent after URS was associated with 1.25 higher odds of ED presentation within 30 days [2]. In another cohort, the rate of unplanned emergency presentations following stent insertion was 7.6%, predominantly due to pain, hematuria and sepsis [14]. These unplanned emergency encounters place significant strain on healthcare systems, contributing to increased bed occupancy, demand on medical and nursing staff, and the need for pathology and radiology investigations, in addition to financial costs. In our study there was a 50.5% cost reduction ($101,117 vs. $51,099) to the hospital due to the reduced number of patients presenting with stent irritation. Patients may also experience work incapacity, with resulting financial and social consequences. In seeking to manage these symptoms, patients also incur the costs of medical consultations and pharmacotherapy, as well as exposing themselves to potential treatment-related adverse effects [6]. The findings of this study demonstrate that reducing stent dwell time significantly decreased the need for emergency care while awaiting URS, with reductions observed both in the proportion of patients presenting to the ED and the frequency of repeat attendances. This effect is likely attributable to the reduced cumulative exposure to stent-related morbidity. Nonetheless, it remains unclear whether the knowledge of a shorter waiting period independently improves a patient’s ability to cope with stent-related symptoms.

The risk of unplanned emergency department presentations among patients with ureteric stents is multifactorial and not solely determined by stent dwell time alone. Previous studies have examined predictors of stent-related symptom severity, identifying associations with younger age, chronic pain conditions, depressive symptoms, and a history of severe stent morbidity [15]. The present study builds on this literature by examining covariates associated with actual emergency department presentations, demonstrating that younger age, immunosuppression, and positive pre-stent urine culture growth are associated with an increased likelihood of presentation during stent dwell. Given that stent dwell time is often influenced by institutional and waitlist constraints, centres facing prolonged waiting periods may benefit from prioritising patients with these higher-risk characteristics for earlier intervention.

Multiple studies have also demonstrated a positive correlation between stent dwell time and infective complications, both in the pre-URS and post-URS setting. In the pre-URS setting, longer stent dwell time was associated with a higher rate of positive urine culture, with dwell times of less than 1 month being associated with a positive culture rate of 4.3%, compared to 26% for patients with a dwell time greater than 1 month [16]. In the post-URS setting, dwell times greater than 1 month were associated with higher sepsis rates. At a dwell time of 1 month, sepsis risk was 1%, rising to 9.2% when dwell time exceeded 3 months [17]. Considered together, these findings suggest that prolonged stent dwell time is associated with higher rates of pre-operative bacteriuria, which may in turn predispose patients to infective complications following URS. Although not statistically significant, our study similarly demonstrated a lower incidence of post-URS infective complications following the policy change (4.2% vs. 2%). However, this study may have been underpowered to detect a statistically significant difference in this outcome.

This study benefits from a large, real-world cohort following an institutional policy change. The end points and covariates were chosen to be clinically relevant and applicable. These findings may support other institutions in auditing their URS and stent-related outcomes, and potentially implement similar policy changes, to hopefully reduce patient morbidity and associated financial burden.

There are, however, several limitations to this study. The retrospective and observational data introduces the potential for confounding and bias, and causality cannot be definitively demonstrated. Although the study cohorts represent patients who underwent treatment in consecutive years with no substantial changes in surgical technique, equipment, or operator practice, unmeasured temporal differences between cohorts cannot be excluded.

While multi-institutional, across a large local health district, the outcomes here may not be representative of the wider population or other institutions, where they may be differing patient demographics, peri-operative protocols and intervention techniques and technologies. Patients who also represented with stent-related complications outside of WSLHD would not be captured within our dataset. A prospective, randomised multi-centre study would help validate these findings and provide further insights into stent-related morbidity.

5. Conclusions

Reducing routine ureteric stent dwell time from 3 months to 1 month may significantly reduce symptom burden and ED presentations, while maintaining safety. Shorter dwell protocols may also reduce healthcare utilisation and patient-incurred economic burden.